Influence of Warm-Mix Additives on Physical, Rheological, and Morphological Properties of High-Viscosity Asphalt

Abstract

The effect of warm-mix additive (WMA) on styrene-butadiene-styrene (SBS)-based high-viscosity asphalt (HVA) was conducted in this study. First, the physical properties for control HVA and HVA with WMA (RH, EC-120, and Sasobit with 2%, 3%, and 4%, respectively) were evaluated to select the optimum WMA. Physical tests showed that all WMAs reduced viscosity (135°C) significantly, while absolute viscosity (60°C) was improved by EC-120 and Sasobit. In addition, EC-120 improved toughness and tenacity. The rheology and morphology of HVA with and without optimum WMA (3% EC-120) were tested using dynamic shear rheometer (DSR), bending beam rheometer (BBR), and scanning electron microscope (SEM). The results indicated that the high-temperature rheological performance was improved by adding EC-120 under unaged and short- and long-term aging conditions. In addition, EC-120 improved the low-temperature creep behavior of the asphalt binder after long-term aging. This finding was further demonstrated by morphological observation, in which a multinetwork was formed after long-term aging.